1. Field of the Invention
This invention relates to booths in which paint is sprayed on to articles to be coated and in particular is concerned with apparatus for scrubbing paint-laden air extracted from such booths.
2. Description of the Prior Art
In U.S. Pat. No. 3,421,293, granted Jan. 14, 1969 there is described a paint-spraying booth which comprises a water-containing trough located beneath and spaced from the floor of the booth, air-extractor means connected with air exhaust ducts which extend lengthwise of and beneath the floor of the booth, at least one tube which extends downwardly from the floor and has the lower end thereof disposed above and spaced from the level of water in the trough, and means arranged to cause a flow of water over the floor and into the tube or tubes. In this arrangement the interior of the tube is provided with vanes arranged to create in air and water passing through the tube a gyratory turbulence which forms the water into small droplets to which at least some of the paint entrained in the air adheres. This arrangement has been found in practice to give very satisfactory scrubbing but the construction of the vanes must be very precise.
It has also been proposed to effect scrubbing of paint-laden air by causing the extractor means to draw the paint-laden air through one or more curtains of water but, as is well understood, water curtains are notoriously difficult to maintain in a continuous state and scrubbing efficiency falls rapidly where there is discontinuity of the curtain or curtains.
It is an object of the invention to provide an improved form of the apparatus first referred to above whereby by the use of a simple construction it is possible to reduce maintenance cleaning to a minimum, to reduce to a minimum the use of water curtains for scrubbing, to provide precise control of operating efficiency to an extent which makes it possible to obtain a more efficient scrubbing than has hitherto been possible, and to provide an apparatus which is capable of scrubbing very small solids particles, for example particles having a size of less than 5.mu., without the use of increased power.